116 resultados para Optimal placement of sensors
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Optimal seeding of a nerve conduit with cells is a core problem in tissue engineering of constructing an artificial nerve substitute to gap lesions in the peripheral nerve system. An ideal nerve gap substitute would have to present an equally distributed number of cells that can activate the regrowing axons. This work shows a new in vitro technique of two-step seeding of cells inside a conduit and on layered mats that allows a valuable targeting of the cells and a proven survival in the environment of poly-3-hydroxybutyrate (PHB) conduits. The technique uses two components of diluted fibrin glue Tisseel. Initially, the chosen area on the mat was coated with thrombin followed from the seeding of a fibrinogen-cell compound. Using Sprague Dawley rat cells, we could demonstrate with immunohistochemistry (S100, DAPI) techniques that undifferentiated (uMSC) and Schwann cells (SC) mimicking differentiated mesenchymal stem cells (dMSC) as well as SC can be suspended and targeted significantly better in dissolvable diluted fibrin glue than in growth medium. Analysis showed significantly better values for adherence (p < 0.001) and drop off (p < 0.05) from seeded cells. Using this two-step application allows the seeding of the cells to be more precise and simplifies the handling of cell transplantation.
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AIM: To investigate the putative modifying effect of dual antiplatelet therapy (DAPT) use on the incidence of stent thrombosis at 3 years in patients randomized to Endeavor zotarolimus-eluting stent (E-ZES) or Cypher sirolimus-eluting stent (C-SES). METHODS AND RESULTS: Of 8709 patients in PROTECT, 4357 were randomized to E-ZES and 4352 to C-SES. Aspirin was to be given indefinitely, and clopidogrel/ticlopidine for ≥3 months or up to 12 months after implantation. Main outcome measures were definite or probable stent thrombosis at 3 years. Multivariable Cox regression analysis was applied, with stent type, DAPT, and their interaction as the main outcome determinants. Dual antiplatelet therapy adherence remained the same in the E-ZES and C-SES groups (79.6% at 1 year, 32.8% at 2 years, and 21.6% at 3 years). We observed a statistically significant (P = 0.0052) heterogeneity in treatment effect of stent type in relation to DAPT. In the absence of DAPT, stent thrombosis was lower with E-ZES vs. C-SES (adjusted hazard ratio 0.38, 95% confidence interval 0.19, 0.75; P = 0.0056). In the presence of DAPT, no difference was found (1.18; 0.79, 1.77; P = 0.43). CONCLUSION: A strong interaction was observed between drug-eluting stent type and DAPT use, most likely prompted by the vascular healing response induced by the implanted DES system. These results suggest that the incidence of stent thrombosis in DES trials should not be evaluated independently of DAPT use, and the optimal duration of DAPT will likely depend upon stent type (Clinicaltrials.gov number NCT00476957).
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Purpose. We describe an atypical case of a patient with Coats disease that re-emerged after 30 years, illustrating a previously poorly understood long-term evolution of the disease. Methods. A 20-year-old man consulted for visual acuity (VA) decrease in the left eye (LE) to 0.3. Fundus examination revealed an exudative lesion with telangiectasias in the superior peripheral retina compatible with the diagnosis of Coats disease. Results. The patient was treated with cryotherapy and argon laser. Visual acuity improved to 0.5 and remained stable during a 1-year follow-up. The patient did not seek further clinical follow-up. Thirty years later, he returned complaining of a progressive VA decrease in the LE. Snellen VA was measured to counting fingers. Fundus examination revealed stage 3A Coats disease with macular exudation and a serous retinal detachment in the inferior quadrants requiring the placement of an encircling band, external drainage, and cryotherapy of the vascular lesions. After 10 additional sessions of argon laser on the vascular malformations, exudation regressed further and best-corrected VA increased to 0.1 at the end of the follow-up period. Conclusions. Coats disease must be considered as a chronic disease, which necessitates a very long-term follow-up even in the absence of subjective visual loss. The disease can reawaken and recur with force in previously unaffected areas of the retina several decades later. The gold standard treatment consists of cryotherapy and argon laser. However, in cases of very important retinal exudation, surgical management with subretinal drainage may be necessary.
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Certain strains of fluorescent pseudomonads are important biological components of agricultural soils that are suppressive to diseases caused by pathogenic fungi on crop plants. The biocontrol abilities of such strains depend essentially on aggressive root colonization, induction of systemic resistance in the plant, and the production of diffusible or volatile antifungal antibiotics. Evidence that these compounds are produced in situ is based on their chemical extraction from the rhizosphere and on the expression of antibiotic biosynthetic genes in the producer strains colonizing plant roots. Well-characterized antibiotics with biocontrol properties include phenazines, 2,4-diacetylphloroglucinol, pyoluteorin, pyrrolnitrin, lipopeptides, and hydrogen cyanide. In vitro, optimal production of these compounds occurs at high cell densities and during conditions of restricted growth, involving (i) a number of transcriptional regulators, which are mostly pathway-specific, and (ii) the GacS/GacA two-component system, which globally exerts a positive effect on the production of extracellular metabolites at a posttranscriptional level. Small untranslated RNAs have important roles in the GacS/GacA signal transduction pathway. One challenge in future biocontrol research involves development of new strategies to overcome the broad toxicity and lack of antifungal specificity displayed by most biocontrol antibiotics studied so far.
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Human tissue biobanking encompasses a wide range of activities and study designs and is critical for application of a wide range of new technologies (-"omics") to the discovery of molecular patterns of disease and for implementation of novel biomarkers into clinical trials. Pathology is the cornerstone of hospital-based tissue biobanking. Pathologists not only provide essential information identifying the specimen but also make decisions on what should be biobanked, making sure that the timing of all operations is consistent with both the requirements of clinical diagnosis and the optimal preservation of biological products. This document summarizes the conclusions of a Pathology Expert Group Meeting within the European Biological and Biomolecular Research Infrastructure (BBMRI) Program. These recommendations are aimed at providing guidance for pathologists as well as for institutions hosting biobanks on how to better integrate and support pathological activities within the framework of biobanks that fulfill international standards.
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With six targeted agents approved (sorafenib, sunitinib, temsirolimus, bevacizumab [+interferon], everolimus and pazopanib), many patients with metastatic renal cell carcinoma (mRCC) will receive multiple therapies. However, the optimum sequencing approach has not been defined. A group of European experts reviewed available data and shared their clinical experience to compile an expert agreement on the sequential use of targeted agents in mRCC. To date, there are few prospective studies of sequential therapy. The mammalian target of rapamycin (mTOR) inhibitor everolimus was approved for use in patients who failed treatment with inhibitors of vascular endothelial growth factor (VEGF) and VEGF receptors (VEGFR) based on the results from a Phase III placebo-controlled study; however, until then, the only licensed agents across the spectrum of mRCC were VEGF(R) inhibitors (sorafenib, sunitinib and bevacizumab + interferon), and as such, a large body of evidence has accumulated regarding their use in sequence. Data show that sequential use of VEGF(R) inhibitors may be an effective treatment strategy to achieve prolonged clinical benefit. The optimal place of each targeted agent in the treatment sequence is still unclear, and data from large prospective studies are needed. The Phase III AXIS study of second-line sorafenib vs. axitinib (including post-VEGF(R) inhibitors) has completed, but the data are not yet published; other ongoing studies include the Phase III SWITCH study of sorafenib-sunitinib vs. sunitinib-sorafenib (NCT00732914); the Phase III 404 study of temsirolimus vs. sorafenib post-sunitinib (NCT00474786) and the Phase II RECORD 3 study of sunitinib-everolimus vs. everolimus-sunitinib (NCT00903175). Until additional data are available, consideration of patient response and tolerability to treatment may facilitate current decision-making regarding when to switch and which treatment to switch to in real-life clinical practice.
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The position of surgery in the treatment of ulcerative colitis (UC) has changed in the era of biologics. Several important questions arise in determining the optimal positioning of surgery in the treatment of UC, which has long been a challenge facing gastroenterologists and surgeons. Surgery is life-saving in some patients and leads to better bowel function and better quality of life in most patients. The benefits of surgery, however, must be weighed against the potential surgical morbidity and compromised functioning that clearly can occur. The introduction of biologic therapy has added further complexity to decisions about medical management, surgery, and the relative timing of these choices. Appropriate medical management of UC may induce and maintain remission and may prevent surgery. However, medical management also carries risks of adverse effects, and recent data suggest that delay of surgery during ineffective medical therapy can increase the chances of negative surgical outcomes. To make individualized timely treatment decisions, early collaboration between gastroenterologists and surgeons is important and more data on predictors of treatment response and positive outcomes are needed. Early identification of patients who would benefit from biologic therapy or surgery is challenging.
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TNF is an essential player in infections with Leishmania major, contributing to the control of the inflammatory lesion and, to a lesser degree, to parasite killing. However, the relative contribution of the soluble and transmembrane forms of TNF in these processes is unknown. To investigate the role of transmembrane TNF (mTNF) in the control of L. major infections, mTNF-knock-in (mTNF(Delta/Delta)) mice, which express functional mTNF but do not release soluble TNF, were infected with L. major, and the development of the inflammatory lesion and the immune response was compared to that occurring in L. major-infected TNF(-/-) and wild-type mice. mTNF(Delta/Delta) mice controlled the infection and resolved their inflammatory lesion as well as wild-type mice, a process associated with the early clearance of neutrophils at the site of parasite infection. In contrast, L. major-infected TNF(-/-) mice developed non-healing lesions, characterized by an elevated presence of neutrophils at the site of infection and partial control of parasite number within the lesions. Altogether, the results presented here demonstrate that mTNF, in absence of soluble TNF, is sufficient to control infection due to L. major, enabling the regulation of inflammation, and the optimal killing of Leishmania parasites at the site of infection.
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The goal of this study was to investigate the impact of computing parameters and the location of volumes of interest (VOI) on the calculation of 3D noise power spectrum (NPS) in order to determine an optimal set of computing parameters and propose a robust method for evaluating the noise properties of imaging systems. Noise stationarity in noise volumes acquired with a water phantom on a 128-MDCT and a 320-MDCT scanner were analyzed in the spatial domain in order to define locally stationary VOIs. The influence of the computing parameters in the 3D NPS measurement: the sampling distances bx,y,z and the VOI lengths Lx,y,z, the number of VOIs NVOI and the structured noise were investigated to minimize measurement errors. The effect of the VOI locations on the NPS was also investigated. Results showed that the noise (standard deviation) varies more in the r-direction (phantom radius) than z-direction plane. A 25 × 25 × 40 mm(3) VOI associated with DFOV = 200 mm (Lx,y,z = 64, bx,y = 0.391 mm with 512 × 512 matrix) and a first-order detrending method to reduce structured noise led to an accurate NPS estimation. NPS estimated from off centered small VOIs had a directional dependency contrary to NPS obtained from large VOIs located in the center of the volume or from small VOIs located on a concentric circle. This showed that the VOI size and location play a major role in the determination of NPS when images are not stationary. This study emphasizes the need for consistent measurement methods to assess and compare image quality in CT.
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Coronary artery fistulae represent the most frequent congenital anomalies of the coronary arteries, but remain a relatively uncommon clinical problem. Moreover, multiple fistulae originating from both the left and the right coronary arteries and draining into the left ventricular chamber are a rare condition. Due to the low prevalence of these anomalies, the appropriate management of patients with symptomatic coronary artery fistulae is controversial. Transcatheter closure approaches have emerged as a less invasive strategy and are nowadays considered a valuable alternative to surgical correction with similar effectiveness, morbidity and mortality. The percutaneous management, however, is mainly limited by the individual anatomic features of the fistula and an appropriate patient's selection is considered as a key determining factor to achieve complete occlusion. Thus, success rates of transcatheter closure techniques reported in the literature are extremely variable and highly dependent upon the nature of the follow up, which, at present, is not standardized. The optimal management of symptomatic patients with multiple coronary artery fistulae still remains a challenging problem and has been traditionally considered as an indication for cardiac surgery. We report here the case of a patient with double bilateral congenital coronary artery fistulae arising from both the left and right coronary arteries and draining individually into the left ventricular chamber. This patient underwent successful transcatheter anterograde closure of both fistulae using a microcoil embolization technique.
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Infection of an intervertebral disk is a serious condition. Diagnosis often is elusive and difficult. It is imperative to obtain appropriate microbiological specimens before initiation of treatment. The authors describe a 51-year-old woman with lumbar spondylodiscitis that was because of infection after the placement of an epidural catheter for postoperative analgesia. A spinal magnetic resonance imaging confirmed the diagnosis, but computed tomography-guided fine needle biopsy did not provide adequate material for a microbiologic diagnosis. Laparoscopic biopsies of the involved disk provided good specimens and a diagnosis of Propionibacterium acnes infection. The authors believe that this minimally invasive procedure should be performed when computed tomography-guided fine needle biopsy does not provide a microbiologic diagnosis in spondylodiscitis.
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PURPOSE: To prospectively evaluate the accuracy and reliability of "freehand" posttraumatic orbital wall reconstruction with AO (Arbeitsgemeinschaft Osteosynthese) titanium mesh plates by using computer-aided volumetric measurement of the bony orbits. METHODS: Bony orbital volume was measured in 12 patients from coronal CT scan slices using OsiriX Medical Image software. After defining the volumetric limits of the orbit, the segmentation of the bony orbital region of interest of each single slice was performed. At the end of the segmentation process, all regions of interest were grouped and the volume was computed. The same procedure was performed on both orbits, and thereafter the volume of the contralateral uninjured orbit was used as a control for comparison. RESULTS: In all patients, the volume data of the reconstructed orbit fitted that of the contralateral uninjured orbit with accuracy to within 1.85 cm3 (7%). CONCLUSIONS: This preliminary study has demonstrated that posttraumatic orbital wall reconstruction using "freehand" bending and placement of AO titanium mesh plates results in a high success rate in re-establishing preoperative bony volume, which closely approximates that of the contralateral uninjured orbit.
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1. Biogeographical models of species' distributions are essential tools for assessing impacts of changing environmental conditions on natural communities and ecosystems. Practitioners need more reliable predictions to integrate into conservation planning (e.g. reserve design and management). 2. Most models still largely ignore or inappropriately take into account important features of species' distributions, such as spatial autocorrelation, dispersal and migration, biotic and environmental interactions. Whether distributions of natural communities or ecosystems are better modelled by assembling individual species' predictions in a bottom-up approach or modelled as collective entities is another important issue. An international workshop was organized to address these issues. 3. We discuss more specifically six issues in a methodological framework for generalized regression: (i) links with ecological theory; (ii) optimal use of existing data and artificially generated data; (iii) incorporating spatial context; (iv) integrating ecological and environmental interactions; (v) assessing prediction errors and uncertainties; and (vi) predicting distributions of communities or collective properties of biodiversity. 4. Synthesis and applications. Better predictions of the effects of impacts on biological communities and ecosystems can emerge only from more robust species' distribution models and better documentation of the uncertainty associated with these models. An improved understanding of causes of species' distributions, especially at their range limits, as well as of ecological assembly rules and ecosystem functioning, is necessary if further progress is to be made. A better collaborative effort between theoretical and functional ecologists, ecological modellers and statisticians is required to reach these goals.
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Large numbers and functionally competent T cells are required to protect from diseases for which antibody-based vaccines have consistently failed (1), which is the case for many chronic viral infections and solid tumors. Therefore, therapeutic vaccines aim at the induction of strong antigen-specific T-cell responses. Novel adjuvants have considerably improved the capacity of synthetic vaccines to activate T cells, but more research is necessary to identify optimal compositions of potent vaccine formulations. Consequently, there is a great need to develop accurate methods for the efficient identification of antigen-specific T cells and the assessment of their functional characteristics directly ex vivo. In this regard, hundreds of clinical vaccination trials have been implemented during the last 15 years, and monitoring techniques become more and more standardized.
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Tools to predict fracture risk are useful for selecting patients for pharmacological therapy in order to reduce fracture risk and redirect limited healthcare resources to those who are most likely to benefit. FRAX® is a World Health Organization fracture risk assessment algorithm for estimating the 10-year probability of hip fracture and major osteoporotic fracture. Effective application of FRAX® in clinical practice requires a thorough understanding of its limitations as well as its utility. For some patients, FRAX® may underestimate or overestimate fracture risk. In order to address some of the common issues encountered with the use of FRAX® for individual patients, the International Society for Clinical Densitometry (ISCD) and International Osteoporosis Foundation (IOF) assigned task forces to review the medical evidence and make recommendations for optimal use of FRAX® in clinical practice. Among the issues addressed were the use of bone mineral density (BMD) measurements at skeletal sites other than the femoral neck, the use of technologies other than dual-energy X-ray absorptiometry, the use of FRAX® without BMD input, the use of FRAX® to monitor treatment, and the addition of the rate of bone loss as a clinical risk factor for FRAX®. The evidence and recommendations were presented to a panel of experts at the Joint ISCD-IOF FRAX® Position Development Conference, resulting in the development of Joint ISCD-IOF Official Positions addressing FRAX®-related issues.